Initially developed to exceed the original SCAR requirements of a multi-caliber, single serial number modular weapon system, the Colt CM901 7.62 x 51 NATO (.308 Winchester) has the modularity and versatility you need. Its free-floating barrel and one-piece monolithic upper receiver provide exceptional accuracy. The revolutionary lower receiver and bolt carrier design enable the upper receiver group to be easily swapped out for any Colt MilSpec upper receiver chambered in 5.56 x 45 NATO (.223 Remington), without tools, in under a minute – allowing the weapon to be reconfigured to any situation at a moment’s notice. All operating controls are ambidextrous, providing you with flexibility and ease of use.